Download - Metamorphic Rock Notes. Formation Metamorphic rocks form by heat, pressure, or a combination of the…
Metamorphic Rock Notes
FormationMetamorphic rocks form by heat, pressure, or a combination of the two.
MetamorphismMetamorphism is a process that changes the shape of something. – Most metamorphism occurs between 50˚C and
1000 ˚C.• (50˚C=122˚F and 1000˚C=1832˚F).
Metamorphic rocks are those whose structure, texture, or composition has changed.
Types of MetamorphismTwo types of metamorphism are contact and regional.
Contact Metamorphism• Magma moves through the crust– Heats surrounding rock and changes it• Increased temperature causes minerals to
change into other minerals• Magma in direct contact with
surrounding rock = greatest change– Greater distance from magma = lower
temperature = less change• Occurs near igneous intrusions
Regional Metamorphism• Pressure builds up in rock buried deep
below other rock formations…– OR large pieces of Earth’s crust collide
with each other• Increased temperature and pressure
cause rock to become deformed and chemically changed
• Occurs deep within Earth’s crust over thousands of kilometers
Composition• Metamorphic rocks are composed of
minerals that change as temperature and pressure are applied.
Calcite
Quartz Hematite
Garnet
Index Minerals• Index minerals are minerals that only
form at certain temperatures and pressures.
• Some common index minerals are biotite mica, chlorite, garnet, kyanite, muscovite mica, sillimanite, and staurolite.
Classification• Metamorphic rocks are classified by
texture. – Texture: The size, shape, or position of
the grains or minerals in a rock
• The texture of metamorphic rocks is broken down into two groups: foliated and nonfoliated.
Foliated• Foliated: The texture
of metamorphic rock in which the mineral grains are arranged in planes or bands
Nonfoliated• Nonfoliated: The
texture of metamorphic rock in which the mineral grains are not arranged in planes or bands.– Commonly made of
only one or a few minerals
Foliated or Nonfoliated?
Foliated or Nonfoliated?
Foliated FoliatedNonfoliated
Metamorphic Rock Flow Chart
Metamorphic Rock
Minerals
Add heat and/or pressure